The present invention relates to an apparatus and method for heating air streams using a refractory radiant-type burner disposed within the air stream. More particularly, the invention relates to such an apparatus and method which minimizes the introduction of noxious burner exhaust emissions into the air stream so that it may be safely used for space heating.
The commonly used forced air furnace systems, while being reasonably efficient for heating multiple room structures, have the disadvantage that they are unable to provide specific space heating for individual rooms. Individual room heat control is important for energy conservation and also to allow the occupant of the room to adjust the temperature to individual taste. In the past, there have been many attempts to provide such individual space heating capability. For the most part, these attempts have involved the use of an additional heating system for each room.
Refractory radiant-type burners have long been suggested for use in forced air heating systems for space heating of buildings and other structures. The operation of such catalytic heaters is well known, for example, as disclosed in U.S. Pat. Nos. 4,318,392, 3,199,505, 3,240,256, 3,421,826, and 3,441,359. One disadvantage of such burners for space heating is that during burner start-up, there is the potential for increased emission levels of noxious burner exhaust elements. Once these burners reach their steady state operating temperature, the production of noxious emissions is greatly reduced.
It is an object of the present invention to provide individual room space heating capability while utilizing the forced air blower system of the central furnace system for the overall structure. It is also an object of the present invention to provide an apparatus for heating an air stream flowing through a conduit, such as the duct system of a forced air furnace system, wherein the apparatus forms a part of the conduit. It is a further object of the present invention to provide a method for heating such air streams which minimizes the introduction of noxious burner exhaust emissions into the air stream.